docs: def _push_tag_buffer(self, data):
          """Write a pending tag attribute from *data* to the stack."""
          if data.context & data.CX_QUOTED:
              self._emit_first(tokens.TagAttrQuote(char=data.quoter))
              self._emit_all(self._pop())
          buf = data.padding_buffer
          self._emit_first(tokens.TagAttrStart(
              pad_first=buf["first"], pad_before_eq=buf["before_eq"],
              pad_after_eq=buf["after_eq"]))
          self._emit_all(self._pop())
          for key in data.padding_buffer:
              data.padding_buffer[key] = ""